If you have the means and desire to have two cars, good for anybody who does (seriously). And, yes, an AWD car with snows would have better traction under acceleration than a comparable RWD car. Personally, I like having one car that can handle anything, a snowstorm in the mountains or a track in 100F heat. Just don't say that the M cannot be driven in severe winter conditions unless you have actually experienced it yourself with the right equipment (tires).

Well said. There's nothing wrong with driving M3's or similar cars in the winter with proper tires, but if someone prefers driving a different car when it snows, so be it. I prefer driving my WRX in the snow, but if I didn't have it, I would certainly be driving my 135 with snow tires.